Classical philosophy and Darwinian biology are far more compatible than is usually assumed. In fact, looking at either from the standpoint of the other can enrich and deepen our appreciation of both. From a Darwinian point of view, the theories of Plato and Aristotle deserve to be taken very seriously. From the classical point of view, Darwinian biology is much less reductionist than its enemies suppose.

Saturday, August 13, 2016

Evolutionary Explanations 3

I have been thinking more about
the concept of play in animals. I wrote
this in a recent post:

The rabbits in my backyard sometimes leap at each other and
seem to dance. This may have some adaptive function, but it looks like
simple fun. A cat toying with a mouse is another example. Good
training for hunting, most likely; but a lot more fun for the one than the other.

Modern biology follows Aristotle’s
lead in carefully distinguishing the explanations we offer in response to why
questions. If I am interpreting the
behavior of the rabbits correctly, it is easy to answer the question “why do
they behave this way?” Because it’s
fun. In the case of the cat playing with
a mouse, this seems almost certain.
Letting the mouse go and catching it again, over and over, isn’t
something the predator does because it’s hungry. Letting it go would risk losing a food
resource, something the cat can afford because it is well fed. It is playing for the sheer joy of it.

Evolutionary explanations need be
deployed when we ask a very different why question. Why are these activities fun? Here again the cat example seems
unambiguous. The animal is in
training. In the case of rabbits, I can
only guess. It didn’t look like mating
behavior and I have no idea what the sex of the players was. It probably has some social function, but I
don’t know anything about social behavior among hares. Almost certainly it has some evolutionary
roots because I assume that what animals like always have such roots. Why do we like vibrant colors? The coevolution of herbivores and oranges explains
that. Why do we like the smell of
cooking meats?

The distinction between the
evolutionary origins of our likes and dislikes and the motives for our actions
is a very powerful one and it helps avoid one of the most frequent confusions
when thinking about Darwinian explanations.
To say that my love for my wife and my children is an expression of
adaptive dispositions is often interpreted to mean that my motives aren’t
genuine. What I really want is to get my
genes into the next generation. Even
Ernst Mayr, one of the geniuses of the philosophy of biology, was guilty of
this. When a bird pretends to be injured
in order to lead a predator away from her offspring, this is ultimately
selfish. She is promoting her own
reproductive success.

This is nonsense. Were I not descended from a very long line of
sexually reproducing animals, I would be very unlikely to be capable of any
kind of love. Because I am so descended,
I am capable of such motives. The latter
serve their evolutionary purpose so effectively precisely because they are
genuine. Whatever I was thinking about
when I invited a young lady to a James Taylor concert, several decades ago, it
wasn’t genetics. When I tenderly cradled
my infant son and daughter in my arms for the first time, I was acting entirely
out of love.

Evolutionary biology is not
reductionist. It is expansionist. It interprets human and non-human behaviors
by reference to a number of robust dimensions, none of which can be reduced to
the others. Those dimension include
psychology and physiology, neurons and neurosis. Some of those dimensions extend backward into
the deep past. Rabbits breed like
rabbits and that is why there are so many of them. This afternoon in my back yard they were just
having a rocking good time.